Weanling Sprague Dawley rat pups (Rattus norvegicus) selected between 2 safe palatable diets in concordance with the preferences of either an adult or a juvenile conspecific model (Experiment 1). Nevertheless, weanlings chose to feed more in the vicinity of an adult than in the vicinity of a juvenile, thus fulfilling the prediction of an adaptive feeding strategy (Experiment 2). The weanlings' ...

Acute and chronic cases of toxoplasmosis in Rattus norvegicus and Rattus rattus mindanensis caught in agricultural, commercial and residential sites in Dasmariñas, Cavite, Philippines were determined serologically. Fifty-eight percent of R. norvegicus and 42.0% of R. r. mindanensis were positive for anti-T. gondii antibodies (Abs). Infection was higher in male rats, and those caught in the comm...

A survey was conducted on rodents from the Riyadh City and surroundings. Two species of fleas, Xenopsylla cheopis and Ctenocephalides felis felis together with Polyplax spinulosa were collected. The highest infestation rate by both fleas occurred on Rattus rattus followed by Rattus norvegicus and Mus musculus. Females of R. rattus and R. norvegicus were more infested by fleas than males. On the...

The authors used laboratory rats (Rattus norvegicus) of known relatedness and contrasting familiarity to assess the potential effect of preexperimental social experience on subsequent social recognition. The authors used the habituation-discrimination technique, which assumes that multiple exposures to a social stimulus (e.g., soiled bedding) ensure a subject discriminates between the habituati...

In this study we examine the size of primary sensory areas in the neocortex and the cellular composition of area 17/V1 in three rodent groups: laboratory nocturnal Norway rats (Long-Evans; Rattus norvegicus), wild-caught nocturnal Norway rats (R. norvegicus), and laboratory diurnal Nile grass rats (Arvicanthis niloticus). Specifically, we used areal measures of myeloarchitecture of the primary ...

Fifteen experimental treatments with rodenticidal baits containing 0.1, 0.15 or 0.2% flupropadine were conducted on farmsteads against Rattus norvegicus infestations. Eight treatments were completely successful and the others gave kills ranging from 36 to 72% in 28 days. Treatments with 0.1 and 0.15% flupropadine were less successful against large infestations than against small ones. Flupropad...

Norway rats were eradicated on bush-covered Hawea Island (9 ha) in Breaksea Sound, using the anticoagulant rodenticide "Talon 50 WB" (brodifacoum). The work was done as a conservation measure and to evaluate the feasibility and costs of eradicating rodents quickly from islands. The 50-100 rats present were eradicated in about two weeks by applying a simple strategy that took full account of the...

In 1926, Crozier and Pincus first reported that 2-week-old rats placed head-down on an inclined plane orient in a head-up direction; this response is called negative geotaxis. In Experiment 1, we replicated this finding by testing 12- to 14-day-old rats on an inclined plane covered with wire mesh. Pups oriented in a head-up direction and avoided the head-down direction at inclines of 45 degrees...

The potential for hantaviral transmission among wild Norway rats by wounding associated with aggressive interactions was evaluated using a prospective sero-epidemiological study coupled with a mark-release-recapture survey. There was a significant association between an animal's serological status and the presence of wounds. Longitudinal studies of marked and released animals showed seroconvers...

We postulate that the large difference in infection prevalence, 24% versus 5%, in R. norvegicus and R. rattus, respectively, between these two co-occurring host species may be due to differences in ectoparasite and potential vector infestation rates. A compartmental model, representative of an infectious system containing these two Rattus species and two ectoparasite vectors, was constructed an...